honnky

Sorry in advance for the dumb question. I have a '74 BB, stock (I think), and the odometer shows 70k (original I think). What type of oil should I be using? Thanks for any input.

Godfathers Ghost

Does it smoke at all? If it does at start up then your valve seals are bad (time, not just mileage effect them) and you can try one of the high milage oils. They actually do work a little. If it smokes continually then its rebuild time but you shoulden't have a problem with this with only 70k. But if it does then go with a traditional oil in the 10w-30 range. If you don't have an issue with smoke then you can free up a few HP by using a synthetic oil, but its not neccesary.

honnky

Thanks for the quick reply. It doesn't smoke at all that I have noticed. After sitting for some time there is some "spray" that comes out of the exhaust (condesation/fuel?) but that is about it. So I should just go with a good quality 10w-30? Thanks.

Godfathers Ghost

Yeah, but as I said, synthetic is good for around 5-10 HP and you can go a couple thou. more miles on it between changes. The spray is condensation like you said and thats normal.

Godfathers Ghost

I almost forgot, synthetics will be a little lower viscosity, around 5w-30 or even 0w-30 like was is used in the C5 & C6.

honnky

Thanks, let me know when you get tired of answering my questions. I am pretty much old school when it comes to oil. What type of synthetic would you recommend?

Godfathers Ghost

Don't worry about it, thats why we hang out on CF The best is Royal Purple, but its a little more money and you probably won't find it localy, get it from Summit, Jegs, or whoever. Other than that, I use Mobile1 syn. in my Silverado and am quite happy with it. Its also happens to be what GM uses on all LS series engins from the factory.

jackson

No offense ... forget the fancy synthetic stuff ... you don't need it ... and you'll never notice the little bit of hp it might yield. You have 40+ year old motor design ... not late stuff that runs VERY tight tolerances.

You won't go wrong with a DIESEL crankcase oil like Rotella 15W-40 or MysticJT8 15W-40 ... either under $3/qt ... even less when bought in gallon/2g/2.5g jugs ... at any parts house, walmart, tractor supply etc. We run it in hi$ circle track race motors & my 71 C3. BTW ... was in new tractor supply here & was not impressed w/ pricing ... BUT ... they has 2g jugs of MysticJT8 15W-40 that is CI4 plus rated for $20/2g jug ... that's $2.50/qt for a syn-blend CI4 plus truck oil. There's plenty of reading here on truck oil ... search. You can change alotta truck oil for the price of hyped RP.

TimAT

The synthetic oil may have a low enough viscosity that it'll leak out of every seal on the engine too. At 70k with the 70's technology, I think I'd stick to a dino oil. IMHO

Godfathers Ghost

Correct about the Rotella, I use it to break in new engines or recomend it for older stuff that has flat tappet lifters and high spring pressures if not using syn. because it has the best additive pkg now that most conv. oil has been reformulated to help with emmisions. But I always recomend syn whenever possible because it is that good. I have seen three differant tests by three differant testers and in every one they picked up at least 5 to 10 HP, one even got 17 but it was a HI-PO engine to begin with. As for the cost, its negligable because you can go nearly twice as long (or more, depending on brand) as convetional oil. It also can withstand higher temperatures then conv. oil, 50 deg. or more, which is great for our sometimes hot running engines. The only negative is that due to its smaller molecules it can get past seals (valve and/or gasket) or minor cylinder scuffs that conv. oil may not. Which is why I asked about any smoke issues first.

Corvette Charlie

Brad Penn 20w-50 (The old "green" Kendall). It has a great additive package with zinc. When you find it (start with an internet search) you wont be disappointed!

SoCalErv

Will leak like a cheap faucet!!

Ray Y

Valvoline 10W-30 Racing oil. This is easy to find and it has high zinc levels. Get a Purolator PUROne filter too.

jack 69

....but 2000 miles later the leaks are gone..(i hope)..BB new with 10-30 mobil one...

noonie

They claim Mobil1 has the additives too
http://www.mobiloil.com/USA-English/...1_15W-50_.aspx

honnky

Wow, thanks for all of the replys....you guys really know your oils. I think howerver I may be more confused now than I was before I asked.

jackson

Sorry ... you know what they say about opinions ... we've all got one ... but here's some solid fact:

Your C3 came with a flat tappet cam & followers and that is an older design (hence “recommended for older valve train designs that may benefit from a higher level of anti-wear normally not required for newer generation vehicles.”) It’s been some 20 years since any major mfg of production cars/lite trucks has OE flat followers … virtually everything since has roller cam & roller followers (hence “newer generation vehicles.”).

In those 20 years, emissions standards have tightened including a requirement that catalytic converters & O2 sensors remain viable for more years & miles.

Flat followers need a higher concentration of anti-wear packages than do roller followers.

Old oil was formulated with good anti-wear packages suited to flat followers but is hard on emissions components.

Newer oil is formulated with a lower concentration of anti-wear packages and do not foul emissions components and provide adequate lube for roller followers but little lube for flat followers.

In those 20 years, MOST car/lite truck oils have reduced anti-wear packages in order to not foul emissions components. Diesel and racing oils are an exception because until MY2007 diesels did not have catalytic converters and pro racers don’t either.

Recently, even diesel oils have reduced anti-wear packs. That change is denoted by the new rating of CJ. Even though the anti-wear pack is reduced in CJ, it still has a good pack. But the older CI4plus is still available and has lots of anti-wear pack those flat followers need to live a long life.

honnky

Again, thanks for all the input. Just a couple more questions...I run Delo 400 15w40 in my 2000 dodge diesel. I read the Delo data sheet and it says meets CI4 plus, CI4, CH4 ect. Would this be ok for my car? And hopefully the last question, my oil pressure runs about 60-70 lbs cold and maybe only drops to 45-50 lbs at temp. Will the heavier oil really mess me up?

jackson

Yes that delo is the good oil ... equivalent to old rotella. You MAY see a little diff in op ...dunno how much you drive in those cold winter ID temps. When it's stone cold outside, I wouldn't hammer it until motor warms a bit ... but I don't do that regardless. Think about this ... LOTSA guys run 20W-50 in first gen sbc/BBC ... lots!

honnky

Thanks for the input Jack. I don't even drive the car unless its above 45 and sunny, so that shouldn't be a problem. I also never "hammer" it.....too scared! I guess the 33 year old thing just gets to me.